Radar Plots
Radar plots present the numeric values of categorical data as a set of points plotted along a set of axes radiating from a central point, with as many axes as there are values in the series and with the points connected by a line, possibly with the interior of the shape filled in. Sequential data values are considered to belong to different categories and are plotted on separate axes which are not necessarily orthogonal and radiate from a central point. Sequential points are connected by a line with the final point connected back to the first to form a closed polygon. The data values from different series are assigned to categories based on the position of the value in the series, for example, the second data value taken from each series all share one category and will therefore all be plotted on the same axis. The data values are plotted along the axis of each class according to their numeric value.
Radar plots do not have any sub-types.
Radar plot styles provide three choices for the rendering of the chart. The first style presents the radar chart as only a polygon of lines. The second style also includes a marker where the data values are plotted on each axis. The third style plots the radar chart as a filled polygon.
This screenshot shows a table of data and three radar plots. The data consist of three series organized by row and starting with the words "Widgets", "Gadgets", and "Lumpets". Each of these series has values in five categories. The three graphs illustrate the three sub-types of radar plots, with the top left plot including lines only, the top right plot including both lines and markers on the points, and the bottom middle plot using filled polygons.
Each series in radar plots can include three main elements and two error elements, although only the value element is necessary. The series can have a 'Name' element, which is a single text entry used to identify the series, must have a 'Values' element, which is a sequence of numeric values, and may have a 'Label' element, which is a sequence of text entries used to identify the categories. All of these elements can be defined as references to a region of the worksheet, as literally defined entries, or as formula expressions which result in the correct type. The 'Label' element is shared by all of the series. The legend added to a radar plot identifies the different series, by default using the entries of the 'Name' element of each series. The two error elements include a list for errors in the positive direction and one for errors in the negative direction.
| Element | Type | Example |
|---|---|---|
| Name | A single textual element labeling the data series. | {"Widgets"} |
| Value | A series of numeric values. | {1293, 2502, 3297, 1100, 2487} |
| Label | A series of textual elements labeling each value. Generally, this series will have as many entries as there were in the 'Value' series. | {"North", "South", "Central", "East", "West"} |
| Error (+) | A list of numeric values with as many elements as there were in the 'Value' list. These values can be in the same units as the numeric values in the 'Value' list, can be proportions or can be proportions multiplied by one hundred. | {0.10, 0.12, 0.09, 0.11, 0.09} |
| Error (-) | A list of numeric values with as many elements as there were in the 'Value' list. These values can be in the same units as the numeric values in the 'Value' list, can be proportions or can be proportions multiplied by one hundred. | {0.08, 0.11, 0.10, 0.09, 0.11} |
Radar plots provide three icons distinguishing the three different styles.
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The icon for a radar plot with the style displaying simple lines only.
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The icon for a radar plot with the style displaying both lines and point markers on the data values.
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The icon for a radar plot with the style displaying a filled area.